PCI: Move test of INTx masking to pci_setup_device
Subsystems (5)
PATCH 1/1 PCI: Move test of INTx masking to pci_setup_device
The test for INTx masking via config space command performed in pci_intx_mask_supported should be performed before PCI device can be used. This is to avoid reading/writing of PCI_COMMAND_INTX_DISABLE register which may collide with MSI/MSI-X interrupts.
This patch simplifies test performed in pci_intx_mask_supported and introduces intx_mask_support field in struct pci_dev to store the result. The test itself is moved to pci_setup_device. The result can be queried at any time later from the pci_dev with
static inline bool pci_is_intx_mask_supported(struct pci_dev *pdev)
{
/*
* INTx masking is supported if device passed INTx test
* and it's INTx masking feature works properly.
*/
return (pdev->intx_mask_support && !pdev->broken_intx_masking);
}Signed-off-by Piotr Gregor <[email protected]>
--- drivers/pci/pci.c | 42 +++++++++++++++++++++++------------------- drivers/pci/probe.c | 3 +++ drivers/uio/uio_pci_generic.c | 2 +- drivers/vfio/pci/vfio_pci.c | 2 +- include/linux/pci.h | 10 ++++++++++ 5 files changed, 38 insertions(+), 21 deletions(-)
drivers/pci/pci.c +23 -19
@@ -3709,42 +3709,46 @@ void pci_intx(struct pci_dev *pdev, int enable)EXPORT_SYMBOL_GPL (pci_intx);/** -* pci_intx_mask_supported - probe for INTx masking support +* pci_intx_mask_supported - probe for INTx masking support in pci_setup_device * @dev: the PCI device to operate on * -* Check if the device dev support INTx masking via the config space -* command word. +* Check if the device dev supports INTx masking via the config space +* command word. Executed when PCI device is setup. Result is saved +* in intx_mask_support field of pci_dev and should be checked +* with pci_is_intx_mask_supported() after PCI device has been setup +* to avoid reading/writing of PCI_COMMAND_INTX_DISABLE register. */ bool pci_intx_mask_supported (struct pci_dev *dev) { -bool mask_supported = false; -u16 orig, new; +u16 orig, toggle, new; +/* +* If device doesn't support this feature though it could pass the test. +*/ if (dev->broken_intx_masking)return false;pci_cfg_access_lock (dev); +/* +* Perform the test. +*/ pci_read_config_word (dev,PCI_COMMAND , &orig); -pci_write_config_word (dev,PCI_COMMAND , - orig ^PCI_COMMAND_INTX_DISABLE ); + toggle = orig ^PCI_COMMAND_INTX_DISABLE ; +pci_write_config_word (dev,PCI_COMMAND , toggle);pci_read_config_word (dev,PCI_COMMAND , &new);/* -* There's no way to protect against hardware bugs or detect them -* reliably, but as long as we know what the value should be, let's -* go ahead and check it. +* Restore initial state. */ -if ((new ^ orig) & ~PCI_COMMAND_INTX_DISABLE ) { -dev_err (&dev->dev,"Command register changed from 0x%x to 0x%x: driver or hardware bug?\n" , - orig, new); - }else if ((new ^ orig) &PCI_COMMAND_INTX_DISABLE ) { - mask_supported = true; -pci_write_config_word (dev,PCI_COMMAND , orig); - } +pci_write_config_word (dev,PCI_COMMAND , orig);pci_cfg_access_unlock (dev); -return mask_supported; + +if (new == toggle) +return true; + +return false; }EXPORT_SYMBOL_GPL (pci_intx_mask_supported);
@@ -3798,7 +3802,7 @@ static bool pci_check_and_set_intx_mask(struct pci_dev *dev, bool mask)* @dev: the PCI device to operate on * * Check if the device dev has its INTx line asserted, mask it and -* return true in that case. False is returned if not interrupt was +* return true in that case. False is returned if no interrupt was * pending. */ bool pci_check_and_mask_intx (struct pci_dev *dev)
drivers/pci/probe.c +3 -0
@@ -1399,6 +1399,9 @@ int pci_setup_device(struct pci_dev *dev) } } +if (pci_intx_mask_supported (dev)) + dev->intx_mask_support =1 ; +switch (dev->hdr_type) {/* header type */ case PCI_HEADER_TYPE_NORMAL :/* standard header */ if (class ==PCI_CLASS_BRIDGE_PCI )
drivers/uio/uio_pci_generic.c +1 -1
@@ -73,7 +73,7 @@ static int probe(struct pci_dev *pdev,return -ENODEV ; } -if (!pci_intx_mask_supported (pdev)) { +if (!pci_is_intx_mask_supported (pdev)) { err = -ENODEV ; goto err_verify; }
drivers/vfio/pci/vfio_pci.c +1 -1
@@ -239,7 +239,7 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev) vdev->nointx = true;pci_intx (pdev,0 ); }else - vdev->pci_2_3 =pci_intx_mask_supported (pdev); + vdev->pci_2_3 =pci_is_intx_mask_supported (pdev); }pci_read_config_word (pdev,PCI_COMMAND , &cmd);
include/linux/pci.h +10 -0
@@ -367,6 +367,7 @@ struct pci_dev { unsigned int __aer_firmware_first_valid:1; unsigned int __aer_firmware_first:1; unsigned int broken_intx_masking:1; + unsigned int intx_mask_support:1; /* INTx masking is supported */ unsigned int io_window_1k:1; /* Intel P2P bridge 1K I/O windows */ unsigned int irq_managed:1; unsigned int has_secondary_link:1;
@@ -1003,6 +1004,15 @@ int __must_check pci_reenable_device(struct pci_dev *);int __must_check pcim_enable_device (struct pci_dev *pdev);void pcim_pin_device (struct pci_dev *pdev); +static inline bool pci_is_intx_mask_supported (struct pci_dev *pdev) +{ +/* +* INTx masking is supported if device passed INTx test and it's INTx +* masking feature works properly. +*/ +return (pdev->intx_mask_support && !pdev->broken_intx_masking); +} +static inline int pci_is_enabled (struct pci_dev *pdev) {return (atomic_read (&pdev->enable_cnt) >0 );
Signature · 1 line
2.1.4
Michael S. Tsirkin
maintainerQuoted 161 lines · Piotr Gregor
The test for INTx masking via config space command performed in
pci_intx_mask_supportedshould be performed before PCI device can be used. This is to avoid reading/writing ofPCI_COMMAND_INTX_DISABLEregister which may collide with MSI/MSI-X interrupts.This patch simplifies test performed in
pci_intx_mask_supportedand introducesintx_mask_supportfield in structpci_devto store the result. The test itself is moved topci_setup_device. The result can be queried at any time later from thepci_devwithstatic inline bool
pci_is_intx_mask_supported(struct pci_dev *pdev){ /* * INTx masking is supported if device passed INTx test * and it's INTx masking feature works properly. */ return (pdev->intx_mask_support && !pdev->broken_intx_masking); }Signed-off-by Piotr Gregor <[email protected]>--- drivers/pci/pci.c | 42 +++++++++++++++++++++++------------------- drivers/pci/probe.c | 3 +++ drivers/uio/uio_pci_generic.c | 2 +- drivers/vfio/pci/vfio_pci.c | 2 +- include/linux/pci.h | 10 ++++++++++ 5 files changed, 38 insertions(+), 21 deletions(-)drivers/pci/pci.c +23
-19@@ -3709,42 +3709,46 @@ void pci_intx(struct pci_dev *pdev, int enable)EXPORT_SYMBOL_GPL (pci_intx);/** -* pci_intx_mask_supported - probe for INTx masking support +* pci_intx_mask_supported - probe for INTx masking support in pci_setup_device * @dev: the PCI device to operate on * -* Check if the device dev support INTx masking via the config space -* command word. +* Check if the device dev supports INTx masking via the config space +* command word. Executed when PCI device is setup. Result is saved +* in intx_mask_support field of pci_dev and should be checked +* with pci_is_intx_mask_supported() after PCI device has been setup +* to avoid reading/writing of PCI_COMMAND_INTX_DISABLE register. */ bool pci_intx_mask_supported (struct pci_dev *dev) { -bool mask_supported = false; -u16 orig, new; +u16 orig, toggle, new; +/* +* If device doesn't support this feature though it could pass the test. +*/ if (dev->broken_intx_masking)return false;pci_cfg_access_lock (dev); +/* +* Perform the test. +*/ pci_read_config_word (dev,PCI_COMMAND , &orig); -pci_write_config_word (dev,PCI_COMMAND , - orig ^PCI_COMMAND_INTX_DISABLE ); + toggle = orig ^PCI_COMMAND_INTX_DISABLE ; +pci_write_config_word (dev,PCI_COMMAND , toggle);pci_read_config_word (dev,PCI_COMMAND , &new);/* -* There's no way to protect against hardware bugs or detect them -* reliably, but as long as we know what the value should be, let's -* go ahead and check it. +* Restore initial state. */ -if ((new ^ orig) & ~PCI_COMMAND_INTX_DISABLE ) { -dev_err (&dev->dev,"Command register changed from 0x%x to 0x%x: driver or hardware bug?\n" , - orig, new); - }else if ((new ^ orig) &PCI_COMMAND_INTX_DISABLE ) { - mask_supported = true; -pci_write_config_word (dev,PCI_COMMAND , orig); - } +pci_write_config_word (dev,PCI_COMMAND , orig);pci_cfg_access_unlock (dev); -return mask_supported; + +if (new == toggle) +return true; + +return false; }EXPORT_SYMBOL_GPL (pci_intx_mask_supported);@@ -3798,7 +3802,7 @@ static bool pci_check_and_set_intx_mask(struct pci_dev *dev, bool mask)* @dev: the PCI device to operate on * * Check if the device dev has its INTx line asserted, mask it and -* return true in that case. False is returned if not interrupt was +* return true in that case. False is returned if no interrupt was * pending. */ bool pci_check_and_mask_intx (struct pci_dev *dev)drivers/pci/probe.c +3
-0@@ -1399,6 +1399,9 @@ int pci_setup_device(struct pci_dev *dev) } } +if (pci_intx_mask_supported (dev)) + dev->intx_mask_support =1 ; +switch (dev->hdr_type) {/* header type */ case PCI_HEADER_TYPE_NORMAL :/* standard header */ if (class ==PCI_CLASS_BRIDGE_PCI )drivers/uio/uio_pci_generic.c +1
-1@@ -73,7 +73,7 @@ static int probe(struct pci_dev *pdev,return -ENODEV ; } -if (!pci_intx_mask_supported (pdev)) { +if (!pci_is_intx_mask_supported (pdev)) { err = -ENODEV ; goto err_verify; }drivers/vfio/pci/vfio_pci.c +1
-1@@ -239,7 +239,7 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev) vdev->nointx = true;pci_intx (pdev,0 ); }else - vdev->pci_2_3 =pci_intx_mask_supported (pdev); + vdev->pci_2_3 =pci_is_intx_mask_supported (pdev); }pci_read_config_word (pdev,PCI_COMMAND , &cmd);include/linux/pci.h +1
-0@@ -367,6 +367,7 @@ struct pci_dev { unsigned int __aer_firmware_first_valid:1; unsigned int __aer_firmware_first:1; unsigned int broken_intx_masking:1; + unsigned int intx_mask_support:1; /* INTx masking is supported */ unsigned int io_window_1k:1; /* Intel P2P bridge 1K I/O windows */ unsigned int irq_managed:1; unsigned int has_secondary_link:1;@@ -1003,6 +1004,15 @@ int __must_check pci_reenable_device(struct pci_dev *);int __must_check pcim_enable_device (struct pci_dev *pdev);void pcim_pin_device (struct pci_dev *pdev);
include/linux/pci.h int __must_check pci_reenable_device(struct pci_dev *); · line 1015
Quoted 10 lines
include/linux/pci.h +9
-0+static inline bool pci_is_intx_mask_supported (struct pci_dev *pdev) +{ +/* +* INTx masking is supported if device passed INTx test and it's INTx +* masking feature works properly. +*/ +return (pdev->intx_mask_support && !pdev->broken_intx_masking); +} +
And now there's pci_is_intx_mask_supported and pci_intx_mask_supported which are the same except pci_intx_mask_supported shouldn't be called by anyone except in one place in pci code.
Pls don't do this. Rename pci_intx_mask_supported -> __pci_intx_mask_supported and then everyone can just keep calling pci_intx_mask_supported as previously, except it'll be faster and safer. And unexport __pci_intx_mask_supported.
Quoted 5 lines
include/linux/pci.h +0
-0static inline int pci_is_enabled (struct pci_dev *pdev) {return (atomic_read (&pdev->enable_cnt) >0 );Signature · 1 line
2.1.4
Quoted 177 lines · On Thu, 25 May 2017 21:22:01 +0300 "Michael S. Tsirkin" <[email protected]> wrote:
Quoted 161 lines · Piotr Gregor
The test for INTx masking via config space command performed in
pci_intx_mask_supportedshould be performed before PCI device can be used. This is to avoid reading/writing ofPCI_COMMAND_INTX_DISABLEregister which may collide with MSI/MSI-X interrupts.This patch simplifies test performed in
pci_intx_mask_supportedand introducesintx_mask_supportfield in structpci_devto store the result. The test itself is moved topci_setup_device. The result can be queried at any time later from thepci_devwithstatic inline bool
pci_is_intx_mask_supported(struct pci_dev *pdev){ /* * INTx masking is supported if device passed INTx test * and it's INTx masking feature works properly. */ return (pdev->intx_mask_support && !pdev->broken_intx_masking); }Signed-off-by Piotr Gregor <[email protected]>--- drivers/pci/pci.c | 42 +++++++++++++++++++++++------------------- drivers/pci/probe.c | 3 +++ drivers/uio/uio_pci_generic.c | 2 +- drivers/vfio/pci/vfio_pci.c | 2 +- include/linux/pci.h | 10 ++++++++++ 5 files changed, 38 insertions(+), 21 deletions(-)drivers/pci/pci.c +23
-19@@ -3709,42 +3709,46 @@ void pci_intx(struct pci_dev *pdev, int enable)EXPORT_SYMBOL_GPL (pci_intx);/** -* pci_intx_mask_supported - probe for INTx masking support +* pci_intx_mask_supported - probe for INTx masking support in pci_setup_device * @dev: the PCI device to operate on * -* Check if the device dev support INTx masking via the config space -* command word. +* Check if the device dev supports INTx masking via the config space +* command word. Executed when PCI device is setup. Result is saved +* in intx_mask_support field of pci_dev and should be checked +* with pci_is_intx_mask_supported() after PCI device has been setup +* to avoid reading/writing of PCI_COMMAND_INTX_DISABLE register. */ bool pci_intx_mask_supported (struct pci_dev *dev) { -bool mask_supported = false; -u16 orig, new; +u16 orig, toggle, new; +/* +* If device doesn't support this feature though it could pass the test. +*/ if (dev->broken_intx_masking)return false;pci_cfg_access_lock (dev); +/* +* Perform the test. +*/ pci_read_config_word (dev,PCI_COMMAND , &orig); -pci_write_config_word (dev,PCI_COMMAND , - orig ^PCI_COMMAND_INTX_DISABLE ); + toggle = orig ^PCI_COMMAND_INTX_DISABLE ; +pci_write_config_word (dev,PCI_COMMAND , toggle);pci_read_config_word (dev,PCI_COMMAND , &new);/* -* There's no way to protect against hardware bugs or detect them -* reliably, but as long as we know what the value should be, let's -* go ahead and check it. +* Restore initial state. */ -if ((new ^ orig) & ~PCI_COMMAND_INTX_DISABLE ) { -dev_err (&dev->dev,"Command register changed from 0x%x to 0x%x: driver or hardware bug?\n" , - orig, new); - }else if ((new ^ orig) &PCI_COMMAND_INTX_DISABLE ) { - mask_supported = true; -pci_write_config_word (dev,PCI_COMMAND , orig); - } +pci_write_config_word (dev,PCI_COMMAND , orig);pci_cfg_access_unlock (dev); -return mask_supported; + +if (new == toggle) +return true; + +return false; }EXPORT_SYMBOL_GPL (pci_intx_mask_supported);@@ -3798,7 +3802,7 @@ static bool pci_check_and_set_intx_mask(struct pci_dev *dev, bool mask)* @dev: the PCI device to operate on * * Check if the device dev has its INTx line asserted, mask it and -* return true in that case. False is returned if not interrupt was +* return true in that case. False is returned if no interrupt was * pending. */ bool pci_check_and_mask_intx (struct pci_dev *dev)drivers/pci/probe.c +3
-0@@ -1399,6 +1399,9 @@ int pci_setup_device(struct pci_dev *dev) } } +if (pci_intx_mask_supported (dev)) + dev->intx_mask_support =1 ; +switch (dev->hdr_type) {/* header type */ case PCI_HEADER_TYPE_NORMAL :/* standard header */ if (class ==PCI_CLASS_BRIDGE_PCI )drivers/uio/uio_pci_generic.c +1
-1@@ -73,7 +73,7 @@ static int probe(struct pci_dev *pdev,return -ENODEV ; } -if (!pci_intx_mask_supported (pdev)) { +if (!pci_is_intx_mask_supported (pdev)) { err = -ENODEV ; goto err_verify; }drivers/vfio/pci/vfio_pci.c +1
-1@@ -239,7 +239,7 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev) vdev->nointx = true;pci_intx (pdev,0 ); }else - vdev->pci_2_3 =pci_intx_mask_supported (pdev); + vdev->pci_2_3 =pci_is_intx_mask_supported (pdev); }pci_read_config_word (pdev,PCI_COMMAND , &cmd);include/linux/pci.h +1
-0@@ -367,6 +367,7 @@ struct pci_dev { unsigned int __aer_firmware_first_valid:1; unsigned int __aer_firmware_first:1; unsigned int broken_intx_masking:1; + unsigned int intx_mask_support:1; /* INTx masking is supported */ unsigned int io_window_1k:1; /* Intel P2P bridge 1K I/O windows */ unsigned int irq_managed:1; unsigned int has_secondary_link:1;@@ -1003,6 +1004,15 @@ int __must_check pci_reenable_device(struct pci_dev *);int __must_check pcim_enable_device (struct pci_dev *pdev);void pcim_pin_device (struct pci_dev *pdev);include/linux/pci.h int __must_check pci_reenable_device(struct pci_dev *); · line 1015
Quoted 10 lines
include/linux/pci.h +9
-0+static inline bool pci_is_intx_mask_supported (struct pci_dev *pdev) +{ +/* +* INTx masking is supported if device passed INTx test and it's INTx +* masking feature works properly. +*/ +return (pdev->intx_mask_support && !pdev->broken_intx_masking); +} +And now there's
pci_is_intx_mask_supportedandpci_intx_mask_supportedwhich are the same exceptpci_intx_mask_supportedshouldn't be called by anyone except in one place in pci code.
Quoted 4 lines
Pls don't do this. Rename
pci_intx_mask_supported->__pci_intx_mask_supportedand then everyone can just keep callingpci_intx_mask_supportedas previously, except it'll be faster and safer. And unexport__pci_intx_mask_supported.
I would additionally suggest not to have pci_dev.broken_intx_masking and pci_dev.intx_masking_support. Let's just use broken_intx_masking to track either broken or unsupported. Then pci_intx_mask_supported() becomes simply "return !pdev->broken_intx_masking;". Of course we skip testing of devices that are already marked by quirks as broken. Thanks,
Alex
Quoted 5 lines
Quoted 5 lines
include/linux/pci.h +0
-0static inline int pci_is_enabled (struct pci_dev *pdev) {return (atomic_read (&pdev->enable_cnt) >0 );Signature · 1 line
2.1.4
Very good suggestions. Will be reflected in changed patch.